<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      String.prototype.say = function () {
        console.log(this);
      };
      const str1 = 'hello1';
      const str2 = 'hello2';
      // String.prototype.split
      str1.say();
      str2.say();
    </script>
  </body>
</html>
